Thromboelastography Parameters Research Articles

Thromboelastography profiles in critically ill children with multisystem inflammatory syndrome.

To describe critically ill children's coagulation profile with the multisystem inflammatory syndrome (MIS-C) related to coronavirus. Single-center, observational study at a tertiary, pediatric intensive care unit (PICU) in children aged 1month to 18years. Sixteen children, with a median age of 5.4years (interquartile range [IQR] 2.1, 11.75), 56% female, admission Pediatric Logistic Organ Dysfunction-2 (PELOD-2) score of 3.5 (IQR 2, 5), and median PICU length of stay 3days (IQR 1.5, 4), met criteria of MIS-C. All patients received acetylsalicylic acid (80-100mg/kg) and none received anticoagulation. Sixty-three percent (10/16) of children had out-of-normal range values on thromboelastography (TEG) (44% [7/16] with hypercoagulability and 19% [3/16] with hypocoagulability). Of those with hypercoagulability, 19% (3/16) had rapid clot formation, and 25% (4/16) had increased clot strength. In 69% (11/16) of children, there was impaired fibrinolysis (0% lysis at 30minutes) on TEG. Seventy-five percent (12/16) of children had out-of-normal range value on standard coagulation assays (37.5% [6/16] with hypocoagulability and 37.5% [6/16] with hypercoagulability). TEG-G (clot strength as measured by TEG) value (ρ -.553, p=.033) and platelet count (ρ -.840, p<.0001) were correlated with admission PELOD-2 score. TEG-G value (ρ -.506, p=.04) and platelet count (ρ -.539, p=.03) were correlated with the duration of intensive care unit stay. Coagulation abnormalities are frequent in children with MIS-C. TEG parameter and platelet count are correlated with the severity of multiorgan dysfunction and the duration of intensive care stay. Multicenter studies are needed to confirm the clinical implications of these coagulation abnormalities.

Sex dimorphisms in coagulation characteristics in the pediatric trauma population appear after puberty.

The role of age and sex in mediating coagulation characteristics in injured children is not well defined. We hypothesize that thromboelastography (TEG) profiles are equivalent across sex in younger children and diverge after puberty. Consecutive trauma patients younger than 18 years were identified from a university-affiliated, Level I, pediatric trauma center (2016-2020) database. Demographics, injury characteristics, and TEG parameters were recorded. Children were categorized by sex and age (younger, ≤10 years; older, ≥11 years). Baseline characteristics, outcomes, and TEG parameters were compared using nonparametric tests as appropriate. To account for the effects of confounding variables, analysis of covariance was performed controlling for Injury Severity Score (ISS), admission Glasgow Coma Scale score, and pediatric age-adjusted shock index. Six hundred forty-seven subjects were identified (70.2% male, median ISS, 10; interquartile range, 5-24; blunt mechanism, 75.4%). Among 395 younger children (≤10 years), there were no differences in TEG characteristics between sexes. Among 252 adolescents (≥11 years), males had greater kinetic times (1.8 vs. 1.4 min; p < 0.001), decreased alpha angles (69.6° vs73.7°; p < 0.001), and lower maximum amplitudes (59.4 vs. 61.5 mm; p = 0.01). Fibrinolysis was significantly lower in older females compared with younger females (0.4% vs. 1.5%, p < 0.001) and age-matched males (0.4% vs. 1.0%, p = 0.02). Compared with younger male children, adolescent males had greater kinetic times (1.8 vs. 1.4 min; p < 0.001), decreased alpha angles (73.5° vs. 69.6°, p < 0.001), lower maximum amplitudes (59.4 vs. 62 mm, p < 0.001), and less fibrinolysis (1.0% vs. 1.3%, p = 0.03). This interaction persisted after controlling for ISS, Glasgow Coma Scale, and pediatric age-adjusted shock index. Sex dimorphisms in TEG coagulation profiles appear after puberty. This divergence appears to be driven by a shift in male coagulation profiles to a relatively hypocoagulable state and female coagulation profiles to a relatively hypercoagulable state after puberty. Prognostic and Epidemiologic, Level III.

Hypercoagulation detected by routine and global laboratory hemostasis assays in patients with infective endocarditis

BackgroundCoagulation system is heavily involved into the process of infective endocarditis (IE) vegetation formation and can facilitate further embolization. In this study we aimed to assess the coagulation and platelet state in IE implementing a wide range of standard and global laboratory assays. We also aim to determine whether prothrombotic genetic polymorphisms play any role in embolization and mortality in IE patients.Methods37 patients with IE were enrolled into the study. Coagulation was assessed using standard coagulation assays (activated partial thromboplastin time (APTT), prothrombin, fibrinogen, D-dimer concentrations) and integral assays (thromboelastography (TEG) and thrombodynamics (TD)). Platelet functional activity was estimated by flow cytometry. Single nuclear polymorphisms of coagulation system genes were studied.ResultsFibrinogen concentration and fibrinogen-dependent parameters of TEG and TD were increased in patients indicating systemic inflammation. In majority of patients clot growth rate in thrombodynamics was significantly shifted towards hypercoagulation in consistency with D-dimers elevation. However, in some patients prothrombin, thromboelastography and thrombodynamics were shifted towards hypocoagulation. Resting platelets were characterized by glycoprotein IIb-IIIa activation and degranulation. In patients with fatal IE, we observed a significant decrease in fibrinogen and thrombodynamics. In patients with embolism, we observed a significant decrease in the TEG R parameter. No association of embolism or mortality with genetic polymorphisms was found in our cohort.ConclusionsOur findings suggest that coagulation in patients with infective endocarditis is characterized by general hypercoagulability and platelet pre-activation. Some patients, however, have hypocoagulant coagulation profile, which presumably can indicate progressing of hypercoagulation into consumption coagulopathy.

The effect of hyperoxia on the hemostasiological status of severely burned patients.

The state of the hemostasis system was studied in 9 patients of the middle age group (44 ± 9.94 years) who received thermal trauma on an area of more than 32% (49.4 ± 18.3) of the body surface, accompanied by the development of burn shock. The standard therapy for burn injury was supplemented with HBO sessions. Treatment with hyperbaric oxygen was carried out in pressure chambers BLKS-307, BLKS-307/1. The state of the coagulation, anticoagulant and fibrinolytic links of the hemostasis system, as well as the viscoelastic properties of the blood, were assessed immediately before the HBO session and immediately after it. The total number of comparison pairs was 45. Under the influence of HBO therapy, there was an increase in the activity of antithrombin III (ATIII), protein C (PrS) and a decrease in the viscoelastic properties of blood (p <0.05). Positive deviations in the values of ATIII, Pr C, von Willebrand factor, APTT, prothrombin and thrombin time, fibrinogen, factor XIII, XIIa-dependent fibrinolysis, D-dimers and thromboelastography parameters were revealed. The maximum frequency of their occurrence was recorded for ATIII (95%), the minimum - for the D-dimer (62%). After HBO procedures, undesirable deviations of the hemostatic system parameters were also noted. They were chaotic, were compensated by an increase in the activity of physiological anticoagulants and were not accompanied by complications of a thrombogenic nature. Thus, conducting HBO therapy sessions in the acute period of burn disease increases the activity of physiological anticoagulants and stabilizes the viscoelastic properties of blood. There is a high frequency of occurrence of positive effects of hyperoxia on the components of the hemostasis system. The identification of its undesirable effects indicates the need to monitor the state of the hemostasis system during HBO procedures.

Recovery of platelet-rich red blood cells and acquisition of convalescent plasma with a novel gravity-driven blood separation device.

ObjectivesOur objectives were to determine the separation characteristics and blood product quality of a gravity‐driven microfiltration blood separation system (HemoClear, The Netherlands).BackgroundA range of centrifugal blood separation devices, including intraoperative cell salvage devices (cell savers) and apheresis machines, are available to assist in preparing both allogenic and autologous blood products. These devices are expensive to operate and require extensive training.Methods and MaterialsNine whole blood units were collected under standard conditions and analysed for haematological parameters, thromboelastographic properties, platelet morphology and activation, and red blood cell (RBC) deformability and morphology. Three whole blood units were separated by means of the HemoClear device, into a liquid and cellular component. The cellular component was diluted with SAGM and cold stored for 14 days. To simulate cell salvage six whole blood units were diluted with isotonic saline, followed by multiple HemoClear separation rounds.ResultsThe recovery of both RBCs (100 ± 1.6%) and white blood cells (99 ± 4.5%) after undiluted filtration were very high, while platelet recovery was high (83 ± 3.0%). During the filtration, and cold storage after filtration storage both the non‐deformable RBC fraction and the RBC maximum elongation remained stable. Parameters of thromboelastography indicated that platelets remain functional after filtration and after 7 days of cold storage. In the cell salvage simulation the total protein load in the cellular fraction was reduced by 65 ± 4.1% after one washing round and 84 ± 1.9% after two consecutive washing rounds.ConclusionThe novel blood filter studied effectively separates whole blood into diluted plasma and platelet‐rich RBCs. Moreover, the device effectively washed diluted whole blood, driving over 80% of proteins to the liquid component.

The evolution of clot strength in critically-ill COVID-19 patients: a prospective observational thromboelastography study

BackgroundFew studies detail the evolution of COVID-19 associated coagulopathy. We performed serial thromboelastography (TEG) and laboratory coagulation studies in 40 critically-ill, mechanically ventilated COVID-19 patients over a 14-day period and analysed differences between 30-day survivors and non-survivors.MethodsSingle-center prospective, observational study including 40 patients with severe COVID-19 pneumonia admitted to the intensive care unit (ICU) for mechanical ventilation. TEG analysis was performed on days 1, 7 and 14 of ICU admission and laboratory coagulation studies were performed on days 1 and 14. Coagulation variables were evaluated for change over the 14-day observation period. Differences between survivors and non-survivors at 30-days were analysed and compared.ResultsOn admission, TEG maximum amplitude (MA) with heparinase correction was above the upper limit of the reference range in 32 (80%) patients while 33 (82.5%) presented with absent clot lysis at 30 min. The functional fibrinogen MA was also elevated above the upper limit of the reference range in 37 (92.5%) patients. All patients had elevated D-dimer and fibrinogen levels, mildly prolonged prothrombin times (PT), normal platelet counts and normal activated partial thromboplastin times (aPTT). The heparinase MA decreased significantly with time and normalised after 14 days (p = < 0.001) while the increased fibrin contribution to clot strength persisted with time (p = 0.113). No significant differences in TEG analysis were noted between 30-day survivors and non-survivors at all time points. No patients developed disseminated intravascular coagulopathy (DIC) after 14-days, however thrombosis and bleeding were each reported in 3 (7.5%) patients.ConclusionCritically-ill patients with COVID-19 present in a hypercoagulable state characterised by an increased clot strength. This state normalises after 14 days despite a persistently increased fibrin contribution to clot strength. We were unable to demonstrate any significant differences in TEG parameters between 30-day survivors and non-survivors at all time points.

COMPARISON OF APTT AND THROMBOELASTOGRAPHY (TEG) TO BLEEDING TENDENCY IN CRITICALLY ILL COVID-19 PATIENTS TREATED WITH HEPARIN

Background: Hypercoagulation in COVID-19 is known to increase the risk of vascular thromboembolism and mortality. Unfractionated Heparin (UFH) is an anticoagulant used to prevent venous thromboembolism. Inadequate dose causes unachieved therapeutic targets, while large dose increases the risk of bleeding. For this reason, the laboratory marker that has most sensitive to detect bleeding tendency is of utmost importance. APTT is a common laboratory test used to therapeutic targets but its sensitivity is still debatable. Thromboelastography (TEG) seems more promising for this purpose in other clinical condition. This study is aimed to compare APTT and Thromboelastography (TEG) in detecting bleeding tendency in critically ill COVID-19 patients treated with heparin. Methods: This study is an analytic observational study in a retrospective design. The method used is total sampling, through several inclusion criteria. Inclusion criteria include: age >18-year-old, confirmed COVID-19 with RT-PCR results, hospitalized in Special Isolation Room, received UFH therapy, and examined for TEG and APTT at the same time. The subjects of this study were divided into two groups, the bleeding and non-bleeding groups. Suitability in APTT between the two groups were analyzed using the Kappa test, suitability in various TEG parameters were analyzed using the Kappa test, and differences APTT and TEG were analyzed using Fisher's exact test. Results: This study showed that there were significant differences in the APTT and had a weak concordance for the incidence of bleeding in these two groups (p: 0,002; k: 0,340); significant differences in various TEG parameters (p < 0,05), namely R time (k: 0,340), K time (k: 1,0), ? angle (k: 0,821), MA (k: 0,701) and CI (k: 1,0), but LY30 no significant difference (p > 0,05). K time and CI had a perfect concordance for the incidence of bleeding. In addition, there was a significant difference in APTT and TEG between the two groups (p: 0.000). Conclusion: TEG shows better description the bleeding condition compared to APTT in critical COVID-19 patients treated with heparin.

181 Impact of Extreme Temperatures on Hemostatic Gauzes Using Thromboelastography

In both military and wilderness/extreme civilian settings, life-threatening hemorrhage can be difficult to control. Hemostatic gauzes provide an excellent option for wounds not amenable to tourniquets. In this study, thromboelastography (TEG) was utilized to evaluate the effect of extreme temperature storage environments on the efficacy of three gauze products. Blood from 30 healthy active duty military adults was diluted by 30% with hetastarch to mimic trauma-induced coagulopathy. Temperatures were chosen because they represented thermal extremes that could be encountered in the tactical setting. Kerlix, Combat Gauze, and Chito Gauze stored for 3 weeks in cold (- 10C), hot (70C), and room-temperature (22C) environments were compared in the TEG parameters of R (time to initiation of clot formation), K (clot amplification), α angle (clot formation rate), and MA (maximum amplitude of clot) using repeated measures ANOVA with the p<.05 statistical significance threshold. Compared to whole blood, diluted blood had weaker clots with slower clot formation kinetics (MA- 58.00 vs 43.00, p<.0001; K- 2.58 vs 4.00, p<.0001; α angle- 54.98 vs 47.36, p<.0003) but faster clot initiation times (R- 8.66 vs 7.14, p<.0001). Addition of any gauze improved clot initiation times (R; Kerlix- 7.14 vs 4.98, p<.0001; Chito Gauze- 7.14 vs 5.22, p<.0001; Combat Gauze- 7.14 vs 2.71, p<.0001), with Combat Gauze significantly improving R over Chito Gauze and Kerlix. Reductions in R values were consistent across temperature extremes (p<.05) The other parameters were consistently unaffected (p>.05) Hemostatic gauze, regardless of temperature storage conditions, improved the rate of initiation of clot formation when compared to diluted blood. Additionally, our results suggest that Combat Gauze may be the best choice for extreme thermal environments.

Increased Plasma Hyaluronan Levels are Associated With Acute Traumatic Coagulopathy.

Acute traumatic coagulopathy (ATC) is an endogenous impairment in hemostasis that often contributes to early mortality after trauma. Endothelial glycocalyx damage is associated with trauma-induced coagulation abnormalities; however, the specific relationship between hyaluronan (HA), a key glycocalyx constituent, and ATC has not been evaluated. We performed a secondary analysis of prospectively collected data from a recent study in which trauma patients (>18 years) admitted to our Level I trauma center with an ABC Score≥2 were enrolled. Partial thromboplastin time (PTT), international normalized ratio (INR), and thromboelastography (TEG) parameters were recorded at arrival. Injury characteristics and clinical outcomes were obtained. Plasma HA levels were measured in healthy controls (HC) and in trauma subjects at arrival (t = 0 h) and 12, 24, and 48 h. ATC was defined as admission INR>1.2 or PTT≥36.5 s. Comparisons of HA levels were assessed, and Spearman's correlations were performed between 0 h and 24 h HA levels, coagulation measures and clinical outcomes. P values < 0.05 were considered significant. Forty-eight trauma patients and 22 controls were enrolled for study. Sixteen trauma subjects were coagulopathic at admission. HA levels in subjects with ATC were higher than non-coagulopathic subjects at all time points and elevated above HC levels at 24 and 48 h. At arrival, HA levels correlated with TEG R-time, PTT, and INR. HA levels at 24 h correlated with increased transfusion requirements and intensive care unit and hospital lengths of stay. Shed HA is associated with early coagulation abnormalities in trauma patients, which may contribute to worse outcomes. These findings highlight the need for additional studies to evaluate the mechanistic role of HA in ATC.

Coagulation profiles and viscoelastic testing in multisystem inflammatory syndrome in children.

To characterize viscoelastic testing profiles of children with multisystem inflammatory syndrome in children (MIS-C). This single-center retrospective review included 30 patients diagnosed with MIS-C from March 1 to September 1, 2020. Thromboelastography (TEG) with platelet mapping was performed in 19 (63%) patients and compared to age- and sex-matched controls prior to cardiac surgery. Relationships between TEG parameters and inflammatory markers were assessed using correlation. Patients with MIS-C had abnormal TEG results compared to controls, including decreased kinetic (K) time (1.1 vs. 1.7minutes, p<.01), increased alpha angle (75.0° vs. 65.7°, p<.01), increased maximum amplitude (70.8 vs. 58.3mm, p<.01), and decreased lysis in 30minutes (Ly30) (1.1% vs. 3.7%, p=.03); consistent with increased clot formation rate and strength, and reduced fibrinolysis. TEG maximum amplitude was moderately correlated with erythrocyte sedimentation rate (ESR) (r=0.60, p=.02), initial platelet count (r=0.67, p<.01), and peak platelet count (r=0.51, p=.03). TEG alpha angle was moderately correlated with peak platelet count (r=0.54, p=.02). Seventeen (57%) patients received aspirin (ASA) and anticoagulation, five (17%) received only ASA, and three (10%) received only anticoagulation. No patients had a symptomatic thrombotic event. Six (20%) patients had a bleeding event, none of which was major. Patients with MIS-C had evidence of hypercoagulability on TEG. Increased ESR and platelets were associated with higher clot strength. Patients were prophylactically treated with ASA or anticoagulation with no symptomatic thrombosis or major bleeding. Further multicenter study is required to characterize the rate of thrombosis and optimal thromboprophylaxis algorithm in this patient population.

Thromboelastography parameters in diagnosing periprosthetic joint infection and predicting reimplantation timing

BackgroundCoagulation-related biomarkers are drawing new attention in the diagnosis of periprosthetic joint infection (PJI). The thromboelastography (TEG) assay provides a comprehensive assessment of blood coagulation; therefore, it could be a promising test for PJI. This study aims to assess the value of TEG in diagnosing PJI and to determine the clinical significance of TEG in analysing reimplantation timing for second-stage revision.MethodsFrom October 2017 to September 2020, 62 patients who underwent revision arthroplasty were prospectively included. PJI was defined by the 2011 Musculoskeletal Infection Society criteria, in which 23 patients were diagnosed with PJI (Group A), and the remaining 39 patients were included as having aseptic loosening (Group B). In group A, 17 patients completed a two-stage revision in our centre. C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), D-dimer, and TEG parameters (clotting time, α-angle, MA [maximum amplitude], amplitude at 30 min, and thrombodynamic potential index) were measured preoperatively in all included patients. In addition, receiver operating characteristic curves were used to evaluate the diagnostic value of these biomarkers.ResultsESR (area under curve [AUC], 0.953; sensitivity, 81.82; specificity, 94.87) performed best for PJI diagnosis, followed by MA (AUC, 0.895; sensitivity, 82.61; specificity, 97.44) and CRP (AUC, 0.893; sensitivity, 82.61; specificity, 94.74). When these biomarkers were combined in pairs, the diagnostic value improved compared with any individual biomarker. The overall success rate of the two-stage revision was 100%. Furthermore, ESR and MA were valuable in determining the time of reimplantation, and their values all decreased below the cut-off values before reimplantation.ConclusionTEG could be a promising test in assisting PJI diagnosis, and a useful tool in judging the proper timing of reimplantation.

Thromboelastography predicts dual antiplatelet therapy-related hemorrhage in patients with acute ischemic stroke

BackgroundStratification of the risk of hemorrhage in patients with acute ischemic stroke following dual antiplatelet therapy (DAPT) is challenging. It remains unclear whether thromboelastography (TEG) can be used to predict...

Does Gender Matter: A Multi-Institutional Analysis of Viscoelastic Profiles for 1565 Trauma Patients With Severe Hemorrhage.

Viscoelastic tests including thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are being used in patients with severe hemorrhage at trauma centers to guide resuscitation. Several recent studies demonstrated hypercoagulability in female trauma patients that was associated with a survival advantage. The objective of our study was to elucidate the effects of gender differences in TEG/ROTEM values on survival in trauma patients with severe hemorrhage. A retrospective review of consecutive adult patients receiving massive transfusion protocol (MTP) at 7 Level I trauma centers was performed from 2013 to 2018. Data were stratified by gender and then further examined by TEG or ROTEM parameters. Results were analyzed using univariate and multi-variate analyses. A total of 1565 patients were included with 70.9% male gender (n = 1110/1565). Female trauma patients were older than male patients (43.5 ± .9 vs 41.1 ± .6years, P = .01). On TEG, females had longer reaction times (6.1 ± .9min vs 4.8 ± .2min, P = .03), increased alpha angle (68.6 ± .8 vs 65.7 ± .4, P < .001), and higher maximum amplitude (59.8 ± .8 vs 56.3 ± .4, P < .001). On ROTEM, females had significantly longer clot time (99.2 ± 13.7 vs 75.1 ± 2.6sec, P = .09) and clot formation time (153.6 ± 10.6sec vs 106.9 ± 3.8sec, P < .001). When comparing by gender, no difference for in-hospital mortality was found for patients in the TEG or ROTEM group (P > .05). Multivariate analysis showed no survival difference for female patients (OR 1.11, 95% CI .83-1.50, P = .48). Although a difference between male and females was found on TEG/ROTEM for certain clotting parameters, no difference in mortality was observed. Prospective multi-institutional studies are needed.

Preventing Thrombohemorrhagic Complications of Heparinized COVID-19 Patients Using Adjunctive Thromboelastography: A Retrospective Study.

Background: The treatment of COVID-19 patients with heparin is not always effective in preventing thrombotic complications, but can also be associated with bleeding complications, suggesting a balanced approach to anticoagulation is needed. A prior pilot study supported that thromboelastography and conventional coagulation tests could predict hemorrhage in COVID-19 in patients treated with unfractionated heparin or enoxaparin, but did not evaluate the risk of thrombosis. Methods: This single-center, retrospective study included 79 severely ill COVID-19 patients anticoagulated with intermediate or therapeutic dose unfractionated heparin. Two stepwise logistic regression models were performed with bleeding or thrombosis as the dependent variable, and thromboelastography parameters and conventional coagulation tests as the independent variables. Results: Among all 79 patients, 12 (15.2%) had bleeding events, and 20 (25.3%) had thrombosis. Multivariate logistic regression analysis identified a prediction model for bleeding (adjusted R2 = 0.787, p < 0.001) comprised of increased reaction time (p = 0.016), decreased fibrinogen (p = 0.006), decreased D-dimer (p = 0.063), and increased activated partial thromboplastin time (p = 0.084). Multivariate analysis of thrombosis identified a weak prediction model (adjusted R2 = 0.348, p < 0.001) comprised of increased D-dimer (p < 0.001), decreased reaction time (p = 0.002), increased maximum amplitude (p < 0.001), and decreased alpha angle (p = 0.014). Adjunctive thromboelastography decreased the use of packed red cells (p = 0.031) and fresh frozen plasma (p < 0.001). Conclusions: Significantly, this study demonstrates the need for a precision-based titration strategy of anticoagulation for hospitalized COVID-19 patients. Since severely ill COVID-19 patients may switch between thrombotic or hemorrhagic phenotypes or express both simultaneously, institutions may reduce these complications by developing their own titration strategy using daily conventional coagulation tests with adjunctive thromboelastography.

Usefulness of Thromboelastography for Perioperative Evaluation of Hemostatic Profile in Patients with Primary Brain Tumors Undergoing Surgery.

Context:Hemostatic abnormalities are more common in patients with brain tumors than systemic malignant diseases. Conventional coagulation tests (CCT) are poor assays for dynamic assessment of clot strength in whole blood. Thromboelastography (TEG) gives us detailed information on the dynamics of clot development, stabilization, and dissolution reflecting in vivo hemostasis. TEG can assess both thrombosis and fibrinolysis.Aims:This study aimed to investigate the temporal trends in hemostatic profile occurring during surgery for primary brain tumors, using a combination of TEG and CCT, and to assess perioperative blood component support.Subjects and Methods:A prospective, observational study was done on 40 patients with primary brain tumors larger than 4 cm in maximum diameter on computed tomography or magnetic resonance imaging. The tests (TEG and CCT [PT, INR, activated partial thromboplastin time, and platelet count]) were performed preoperatively (on the day of surgery), intraoperatively (2 h into surgery), and postoperatively (the day after surgery).Statistical Analysis:SPSS Version 21.0 statistical analysis software was used.Results:We found a universal trend toward hypercoagulability (persistent decrease in R-time, K-time and increase in MA, α-angle, Coagulation Index) in all the TEG parameters measured intraoperatively and postoperatively even though the values were within normal limits. Results of CCT had poor correlation with TEG parameters. The mean intraoperative blood loss was 737.7 ± 185.6 mL, for which PRBC was transfused in 17 patients, FFP in 13, but no platelet transfusion was done intraoperatively.Conclusions:We found a trend toward hypercoagulability in our study in intraoperative and postoperative period using TEG which was not evident on CCT. TEG was a useful diagnostic tool to identify coagulation abnormalities and to guide perioperative blood transfusion.

The Use of Thromboelastography in Monitoring Coagulation Status for Patients Treated with Low Molecular Weight Heparin, Warfarin, Apixaban, and Rivaroxaban

Introduction: Thromboelastography (TEG) is used to rapidly assess global coagulation status. A few studies in the literature have explored a possible role for TEG in anticoagulant monitoring, with conflicting observations. We wondered if TEG might be used adjunctively with traditional markers of anticoagulation as a measure of anticoagulant efficacy. We hypothesized that some of these variations might be due to changes in certain coagulation factor levels.Methods: Blood samples were collected from patients on therapeutic doses of warfarin, low molecular weight heparin (LMWH, enoxaparin or dalteparin), or an anti-Xa direct oral anticoagulant (DOAC, apixaban or rivaroxaban) due to a history of thrombosis. TEG was performed on all samples with and without addition of heparinase; R time, K time, alpha-angle, maximum amplitude, and percent of clot lysis after 30 minutes were measured. Standard anticoagulation parameters were obtained at the same time as TEG values [prothrombin time (PT) and activated partial prothrombin time (PTT) for warfarin- and DOAC-treated patients; anti-Xa level for LMWH-treated patients]. For each patient, pertinent medical history was recorded including: age, medical comorbidities, and thrombotic history. Von Willebrand factor (vWF) antigen level, factor VIII (fVIII) activity, anti-Xa, and R time were examined in a follow-up cohort of enoxaparin-treated patients. Correlation between TEG and anticoagulation parameters was analyzed using Spearman correlation coefficient (r).Results: Forty-six patients participated in this study. Median age was 52 years (range, 20-83). The most common indication for anticoagulation was deep venous thrombosis or pulmonary embolism (N = 33); 5 subjects had active cancer at the time of anticoagulation testing (all on LMWH). Among warfarin-treated patients (N = 19), INR was significantly correlated with R time (Figure 1, p=0.005), with 4 patients demonstrating a prolonged R time of over 10 min. Among patients on LMWH (enoxaparin, N = 13; dalteparin, N = 1), 5 had a prolonged R time, but there was no correlation between anti-Xa level and R time, R time ratio or R time difference with or without heparinase, or any other measured TEG parameter when analyzing all LMWH patients or only enoxaparin-treated patients as a function of total daily enoxaparin dose. Among DOAC patients (apixaban, N = 6; rivaroxaban, N = 8), R time was not elevated in any of the samples, but there was a significant correlation between PTT and R time (p=0.006). Four study patients had recurrent thrombotic events (1 with antithrombin deficiency, chronic liver disease, and bowel resection, on warfarin; 1 with May-Thurner syndrome, on LMWH; 2 with metastatic cancer and Trousseau's syndrome, also on LMWH) in spite of therapeutic INR or anti-Xa levels; these patients were all found to have normal R times on TEG. In a follow-up analysis of 8 enoxaparin-treated patients, 6 had normal and 2 had prolonged R times. All 6 with normal R times had elevations in vWF and/or fVIII, while the 2 with prolonged R times had normal levels of vWF and fVIII.Conclusion:TEG R time is significantly correlated with INR in patients on warfarin. TEG R time is also correlated with PTT in patients on DOACs. For both DOACs and warfarin, TEG could be useful in rapidly assessing the coagulation status of patients who present with emergent bleeding and may benefit from reversal agents. In patients on LMWH, TEG R time is affected by circulating levels of vWF and fVIII. For select patients on LMWH, TEG may be helpful as an adjunctive measure of anticoagulant activity in cases where anti-Xa monitoring may not be accurate. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Utility of Global Coagulation Assays in Myeloproliferative Neoplasm: Thromboelastography, Thrombin Generation and Overall Haemostatic Potential

IntroductionMyeloproliferative neoplasm (MPN), such as polycythaemia vera (PV) and essential thrombocythaemia (ET), are independent risk factors for arterial and venous thrombotic events, with the estimated risks of thrombotic complications at diagnosis to be approximately 7-26% in ET patients and 19-32% in PV patients. As such, one of the management goals for MPN is directed towards modifying thrombosis risk via cytoreduction and anti-platelet therapies. However, there are no routinely available laboratory tests to evaluate the patient's thrombotic risk beyond the assessment of blood counts. Global coagulation assays such as thromboelastography, thrombin and fibrin generation may be better surrogate measures of thrombosis. This pilot study evaluates a cohort of MPN patients on current treatment, to further elucidate the impact of their prothrombotic milieu on global coagulation assays.MethodsParticipants with MPN (proven on bone marrow biopsy and/or molecular diagnosis) were recruited. Thromboelastography (using TEG® 5000) was performed on citrated whole blood while additional citrated blood samples were double spun at -2500G to obtain platelet-poor plasma (PPP) and stored in at -80°C within 2 hours of sample collection. The stored PPP were then used for thrombin generation assessment using the calibrated automated thrombogram (CAT), fibrinolysis evaluation using overall haemostatic potential assay (OHP) as well as p-selectin testing. The results were compared to our previously collected age-matched healthy normal controls (n=41).ResultsThirty-eight MPN patients (20 females, 18 males) with median age 65 years (range: 29-84) were recruited. There were 26 patients with ET (68.4%) including a patient with post-ET myelofibrosis, 8 patients with PV (20.5%), 3 patients with primary myelofibrosis and one with MPN, unclassifiable. The majority of the patients are JAK2 V617F positive (30/38, 79%). The haemoglobin level was comparable between both groups (p=0.73) although the MPN group had significantly increased platelet count (526 vs 237 x 109/L, p<0.01).When compared to normal controls, the thromboelastography parameters were mostly comparable including no significant difference in maximum amplitude or clot strength (59.6 vs 60.1 mm, p=0.42) although the clot lysis time (LY30) was significantly higher (5.1% vs 0.9%, p<0.01) in the MPN group, independent of the use of aspirin. Higher LY30 (>5%) was associated with higher haemoglobin (150.3 vs 138.4 g/L, p=0.03) but not platelet count. CAT parameters, however, showed higher thrombin peak (260.8 vs 227.3 nM; p=0.01) and velocity index (93.4 vs 70.1 nM.min; p<0.01) compared to the normal controls, but interestingly no difference in endogenous thrombin potential (1397.5 vs 1363.0 nM.min, p=0.52).Fibrin generation parameters, namely the overall coagulation potential (OCP) and OHP were significantly reduced in the MPN cohort (OCP - 56.5 vs 66.7, p<0.001; OHP - 27.4 vs 33.0, p<0.001) with preserved overall fibrinolytic potential (p=0.66). P-selectin was markedly increased in MPN patients compared to the normal controls (116.3 vs 54.6 ng/mL, p<0.001), with higher P-selectin levels correlating with a higher platelet counts (p<0.01).ConclusionThis study demonstrates that global coagulation assays can provide additional information regarding the thrombotic risks in MPN patients. The MPN patients in our study had significantly higher lysis time and a reduction in fibrin generation parameters, which is contradictory to the prothrombotic nature of MPN. It may be a protective prognostic marker in the setting of treatment and could represent an underlying compensatory effect. Despite being a treated MPN cohort, the P-selectin remained higher in these patients and correlated with higher platelet count, suggesting that the higher P-selectin seen is likely of platelet subtype, though this did not correlate with changes in other global coagulation assay parameters despite thrombin being a known trigger of P-selectin exocytosis. Further prospective clinical studies including assessment of fibrinolysis markers and markers of platelet and endothelial function to evaluate and confirm these findings are proposed. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Comparison between thromboelastography and conventional coagulation assays in patients with deep vein thrombosis

BackgroundConventional coagulation assays (CCAs) are of limited value in the assessment of coagulation status in patients with deep vein thrombosis (DVT). We aimed to compare thromboelastography (TEG) and CCAs in identifying DVT and evaluating coagulation status in DVT patients. MethodsSixty-six patients diagnosed with DVT and forty healthy controls were enrolled. Blood samples were collected within 4 h of patients’ admission to hospital before any operation and tested by TEG and CCAs. TEG and CCA parameters were compared between DVT patients and controls. The ability of each parameter in identifying DVT was assessed. Pearson’s correlation was used to determine the correlation between TEG and CCA parameters among the study population. ResultsTEG showed significant differences between DVT patients and controls, indicating a hypercoagulable tendency in patients suffering from DVT. In contrast, no significant difference regarding CCAs was observed between the DVT and control group. Furthermore, TEG displayed a better capacity in identifying DVT than CCAs. In addition, Pearson’s correlation analysis showed TEG and CCA parameters had few correlations. ConclusionTEG has advantages in identifying DVT and detecting hypercoagulability, and provides a better insight in evaluating coagulation status in patients with DVT than CCAs.

Thromboelastography (TEG) results are predictive of ischemic and hemorrhagic complications in patients with unruptured intracranial aneurysms treated with flow diversion.

Flow diversion is an effective treatment modality for intracranial aneurysms but is associated with ischemic and hemorrhagic complications. Patients treated with flow diversion require dual antiplatelet therapy and subsequent platelet function tests. At our institution, Thromboelastography with Platelet Mapping (TEG-PM) is the test of choice. The primary objective of this study was to identify TEG parameters that are predictive of postoperative complications in patients treated with elective flow diversion. This was a retrospective study of 118 patients with unruptured intracranial aneurysms treated with flow diversion. Data was collected via chart review. Bivariate analyses were performed to identify significant variables in patients who suffered an ischemic stroke or a groin hematoma. ROC curves were constructed for the TEG parameters with statistical significance. Bivariate analyses were repeated using dichotomized TEG results. Patients who experienced a symptomatic ischemic stroke had a history of stroke (p value = 0.007), larger aneurysm neck width (p value = 0.017), and a higher alpha angle (p value = 0.013). Cut off point for ischemic complication is 63° on ROC curve with a sensitivity of 100% and specificity of 65%. Patients who experienced a groin hematoma were no different from their healthy peers but had a lower alpha angle (p value = 0.033). Cut off point for hemorrhagic complication is 53.3° with a sensitivity of 82% and specificity of 67%. The Alpha Angle parameter of TEG-PM has a sizeable predictive ability for both ischemic complications of the central nervous system and hemorrhagic complications of the access site after elective flow diversion.

Association of thromboelastography profile with severity of liver cirrhosis and portal venous system thrombosis

Background and aimHemostasis profile is often complicated in liver cirrhosis. Thromboelastography is a global viscoelastic test recommended by the current practice guideline and consensus. This cross-sectional study aimed to evaluate the association of thromboelastography profile with severity of liver cirrhosis and presence of portal venous system thrombosis (PVST).MethodsOverall, 116 and 50 cirrhotic patients were included in the Shenyang and Xi’an cohorts, respectively. Thromboelastography parameters were compared between cirrhotic patients with Child–Pugh class A and B/C, those with and without decompensated events, and those with and without PVST. Hypercoagulability would be considered if at least two of the following thromboelastography parameters were met: shortened reactive time (R), shortened coagulation time (K), increased angle, and increased maximum amplitude (MA).ResultsIn the Shenyang cohort, 16 patients had shortened R, of whom seven (43.75%) had prolonged K and 11 (68.75%) decreased MA. In the Xi’an cohort, 24 patients had shortened R, of whom seven (29.17%) had prolonged K and 15 (62.50%) decreased MA. In the Shenyang cohort, the prevalence of hypercoagulability was not significantly different between cirrhotic patients with Child–Pugh class A and B/C (3.85% vs. 6.25%, P = 0.873), those with and without decompensated events (5.49% vs. 4.00%, P = 1.000), and those with and without PVST (4.17% vs. 5.88%, P = 1.000), which were similar to the results obtained in the Xi’an cohort.ConclusionThere is a high rate of discordance between R and other thromboelastography parameters. In addition, hypercoagulability may not be related to more advanced stage of liver cirrhosis or presence of PVST.